After installing the new MAF on my 80, I also am trying a experiment with the intake duct. The stock intake is a plastic box, clamped to the filter housing that is mounted inside the fender. The inlet to the box is at the top of the fender. It looks like a nice design to reduce the chance of water getting sucked in. My experiment is to replace the box with a duct routed to the front of the truck with the goal of improving air flow to the filter and reducing the intake air temperatures. I wasn't able to get the "before" measurements in the stock config, but I was able to grab some data on the way home from Breckenridge Brewery last night with my new duct. Jeff Z was nice enough to lend me his ScangaugeII so I can measure the temps.

I had a thermocouple wire hanging out the window for my ref temp. It was about 68-69 F on the ride home. The Scangauge was reporting about 76F on the highway and 86 to 93F once I got into low speed traffic and stoplights. So the first data points are an 8 degF temp rise on the highway and an 24ish Deg temp rise around town. I'll run it some more to see how it does when the ambient temp is higher during the day.

Does anyone have some data on the temp rise from the stock intake config?

That's alright, we chat enough it tech that maybe this will balance out. Bruce, can you put your light back in and be close enough to replicating the stock setup? I'm impressed that the highway temp is so cool, that's got to be better than before.

corsair23

06-02-2008, 02:15 AM

I'm impressed that the highway temp is so cool, that's got to be better than before.

x2 :D

Bruce and I chatted about this the other night. I'm working off of memory but I am almost 100% POSITIVE those are some incredibly low IA temps. The last time I paid attention to the IA was last year on a drive to Steamboat. I was reading the booklet that comes with the Scangauge and it says on the highway the IA temp should be just slightly higher than the ambient temp. Well, IIRC I figured the IA temps I was seeing were 50F+ higher than ambient, and probably higher than that, during the roadtrip to Steamboat. It was about that time as well that Ken was looking for ways to reduce his underhood temps and I came across a picture of where Rick (Landtank) had once wrapped a winter coat around his air filter can that resulted in lower IA temps :hill:

Maybe Hants will chime in with some data as he has the MAF mod with the stock air inlet AND a Scanguage II :thumb:. Otherwise Bruce, when I get the Scangauge back I can take some measurements albeit without the MAF mod being done yet. Or, we can slap the Scangauge II into Farr's truck for the trip to Rubicon and get all sorts of data points :)

Hants

06-02-2008, 08:42 AM

Maybe Hants will chime in with some data as he has the MAF mod with the stock air inlet AND a Scanguage II :thumb:.

Out of town (again) right now, so not much help here.

I don't remember seeing a dramatic drop in IAT after the MAF upgrade. It takes a few minutes of highway speeds, but then my IAT would usually drop to 10-20 degrees above ambient.

Around town, 3-5 times ambient is not surprising (I've seen well over 100 when its below 50 outside).

I haven't looked for a while. I'll pay attention again and post up if I see anything different.

P.S. A snorkle is in my future... and maybe some heat wrap for the air filter. :hill:

corsair23

06-02-2008, 04:49 PM

Thanks Hants :thumb:

I don't think the MAF mod makes much of a difference other than apples-to-apples comparison. Although, the MAF mod is supposed to freer flowing so maybe it'll make a slight difference. I don't know where the IA temp sensor is though...

Hants

06-02-2008, 05:45 PM

I don't know where the IA temp sensor is though...

It's right there in the MAF housing. The MAF needs the IAT sensor to accurately read the flow rate. Take a look at the sensor before you install it.

corsair23

06-02-2008, 10:14 PM

:doh:

Makes sense :D

corsair23

06-10-2008, 07:12 PM

I had a thermocouple wire hanging out the window for my ref temp. It was about 68-69 F on the ride home. The Scangauge was reporting about 76F on the highway and 86 to 93F once I got into low speed traffic and stoplights. So the first data points are an 8 degF temp rise on the highway and an 24ish Deg temp rise around town. I'll run it some more to see how it does when the ambient temp is higher during the day.

Does anyone have some data on the temp rise from the stock intake config?

Ok, I've been remiss in typing this up :rolleyes:...

Bruce, on the way home from the meeting last week I monitored the IA temp. As I was going by Bandimere their sign showed the air temp was 53F. Since I don't have way to measure outside air temp we'll have to use this as the baseline ambient air temp :)

On the highway, the IA temps were pretty stable from Bandimere home and fluctuated between 76-78F.

Once off the highway on the side roads that average 30-45mph the IA temp rose steadily reaching 100F.

I stopped to get the mail and in that time the IA temps rose to 105F. Parked in the driveway as I was shutting the rig down the IA temp showed 110F.

Over the next couple days I monitored the IA temps in the morning, using using the reported IA temp shortly after startup as the ambient temp. Typically they were in the mid 60s at start. So, lets assume a 65F IA temp on these days. After a 15-20 min drive on side roads, and in stop and go traffic, the IA temps would reach in the 110-120F range. On a particular day I wrote down the numbers I started with a baseline/ambient temp of 64F and upon reaching work 15-20mins later on side roads the IA temp read 119F.

What I have noticed is when the engine is up at operating temp, it really starts to "heat soak" the air filter can, MAF housing, and IA tube areas. Considering where Nakman has the snackster mounted, this heat soaking isn't a surprise. I have not checked to see how the IA temps behave once the area is heat soaked and then I get on the highway but based on past experience I don't believe the IA temps come down all that much.

The above #'s are using the stock MAF and stock MAF housing. I will be interested to see if the Landtank MAF housing and the new MAF will make any difference (more sensitive, not as prone to heat soaking, whatever) but it would appear that your experimental intake air duct makes about a 50% difference. That is a good thing as we all know colder air = denser air = better combustion etc. :thumb: :cool:

nakman

06-10-2008, 10:29 PM

I like where this is headed, and have always thought more=better and cooler=better. But what about Red Chili's cooler air=use more gas theorem (http://www.risingsun4x4club.org/forum2/showpost.php?p=75905&postcount=10)?

I can see this argued the other way, and using more gas would be a big step in the wrong direction, IMO. Bruce, any difference in MPG that you notice? :confused:

Hants

06-10-2008, 11:28 PM

More/colder air = greater efficiency (&quot;VE&quot;) ==> less throttle for same output

Think of it in the extremes. 1&quot; intake = really high vacuum to get flow = not very efficient. No air filter, 6&quot; intake = virtually no vacuum to get flow = something else is the bottleneck.